LONDON — Europe’s leaders are trying to nail down their plans to back up Ukraine with multinational military force if the country manages to land a peace deal with Russia.

With a flurry of diplomacy towards an agreement sharpening minds, Ukraine’s allies assembled for a virtual meeting of the “coalition of the willing” Tuesday — and appeared to have won at least some United States buy-in.

The meeting was designed to show solidarity with Kyiv as it advances delicate peace talks with the U.S. — and make good on promises by the 33-strong “Coalition of the Willing” to match words with deeds.

On Tuesday night, French President Emmanuel Macron announced a new joint task-force — led by France and the U.K. with the participation of the United States and Turkey. It’s intended to hammer out the precise detail of the military support Europe will offer under a peace agreement.

“In the coming days, we will be able to finalize very precisely the contributions of each country and be able to present finalized security guarantees,” Macron promised.

A “multinational force” will play “a vital part” in guaranteeing the country’s security, British Prime Minister Keir Starmer told those on the call — who notably included U.S. Secretary of State Marco Rubio.

An Elysée official argued that the fresh task force would give a “new coherence” to transatlantic talks on security guarantees, while a U.K. official said Rubio’s participation in the call was a positive sign of U.S. buy-in, long one of the most contentious elements of any plan. A second British official said British preparations by military planners were “very well advanced.” 

Still, analysts urged a good dose of caution.

Ed Arnold from the Royal United Services think tank in London warned that, if U.S. security guarantees are not firmly pinned down, the coalition is “in a really dangerous position, in that you’re deploying a force with a backstop that deep down you know is not credible.”

‘Fallback positions’

The coalition, a loose alliance of nations whose members include France, Germany, Britain, Belgium, Canada and Turkey among others, sprung up earlier this year amid deep European concern about America’s ongoing support for Ukraine.

Its members have promised varying degrees of support — including, in the case of France and the U.K., a commitment to deploy national troops on the ground to police the deal and deter further Russian aggression.

The coalition has already floated a “reassurance force” providing air and naval support to Ukraine, as well as a focus on regenerating the country’s armed forces. Starmer’s spokesman told reporters Tuesday that the U.K. was “still willing to put boots on the ground” to secure peace. Macron, while stressing that the force would be “far from the frontline,” floated a presence “in fallback positions in Kyiv or Odessa.”

“We’ll have a air reassurance force, which will not be based in Ukraine, but possibly in neighboring countries… leading operations linked with the Ukrainian air force to secure its airspace,” he told French radio.

With one eye on a wary domestic audience, Macron added: “We shouldn’t sow panic among the French, because there are a lot of people… who want to scare us, and who are saying that we’re going to immediately send troops, that’s false.”

Germany has been somewhat more circumspect about its involvement. Foreign Minister Johann Wadephul this week pointed to an existing German brigade in Lithuania, saying “we are more involved in the entire region than almost any other member of NATO” and that this is “sufficient.”

Major questions remain too about how the U.S. really sees its own role and where European forces could make a tangible difference. Russia has openly trashed a Europe-backed plan for peace.

Calvin Bailey, a Labour MP on the U.K. House of Commons defense committee, said that while the group is “playing a vital role… the capabilities and plans we offer in to this process must be properly resourced and credible for this to work.” The U.K. Conservative Party has questioned whether the government has really thought its commitments through.

The second British government official cited above insisted this criticism was misplaced, arguing clear operational expectations can only be set after a ceasefire agreement is actually reached. 

But John Foreman, former British military attaché to Russia, played down the significance of Europe’s military contribution as a whole.

He argued that the coalition’s main utility is “as a political grouping which can bridge NATO, EU and the rest of the world.”

It is, he said, “never going to be able to provide credible security guarantees — only the U.S. with perhaps key allies can do this, as no one wants to fight the Russians if peace breaks down.”

Nette Nöstlinger contributed to this report.